There is not a more exciting heavyweight in boxing than Tyson Fury. He is not Mike Tyson, after whom he was named 23 years ago, and there can be no guarantee he will become a world champion – although he has a better chance than many of his peers – but, in retaining his Commonwealth title after visiting the floor for the first time in his career on Saturday, the charismatic Gypsy confirmed it would be foolish to dismiss him as a passing storm.

Sixteens seconds from the end of the third round, Fury composed himself long enough to gather his strength and pound the Canadian Neven Pajkic to the canvas, although the loser was not convinced he was finished; he even interrupted the ring announcer's acclamation of the champion after the fight but it was as futile a gesture as were his final punches.

This defence was a sharp reminder, nonetheless, for the champion that he needs to stay focused. He was curiously disengaged early and paid the price for his complacency before finding his mojo.

Fury always comes to fight. It is the core of his being. On Saturday night, in the middle of a shopping complex on the edge of the city that perhaps did not stir the fighting juices, he struggled to rouse himself against an anonymous fighter nearly two stones lighter but just a little bit more switched on.

At this weight, there is no room for swagger. If Fury imagined Pajkic was coming here to fall over he was very quickly disabused of the notion.

In round two, Fury raised both hands in the air and whacked the cheeky visitor with head shots that delighted the small gathering. Jubilation did not last long. There were mutual swings and misses before Pajkic struck home a chilling right to the chin of the home town favourite, to sit Fury on the seat of his pants for the first time in his fighting life. Now we had a fight.

Stung but still not totally switched on, Fury discovered his game in round three. He measured his man with pawing lefts, followed by sledgehammer rights and the shopping mall came to life. A couple of clubbing rights put the Canadian down and Fury was excited again. Another left put Pajkic on the floor one more time, and he shipped a further flurry before the referee stepped in – prematurely but much to the relief of Fury's supporters.

"I got myself a shock there for sure," Fury said of being knocked down. "He got me with a good shot, but I got up and stopped him."

There was a neat narrative on the undercard. In a week of boxing nostalgia, a reincarnation of a fine and eccentric British world champion, Chris Eubank, announced his arrival in the professional ranks with a perfunctory spar that brought him a fourth-round win against a pacifist called Kirilas Psonko. But as with Eubank Sr, the kid brought style, quality of hitting and a back story.

The 25-year-old Lithuanian, Psonko, arrived from Klaipeda with eight wins from 15 outings and had been stopped six times. He was, nevertheless, not a total mug: he had gone six rounds with the Commonwealth champion George Groves on the Londoner's professional debut three years ago.

But he has turned into a serial loser of late and threw fewer punches than the number of journalists who gathered around Eubank after the fight. Eubank Jr is managed by Ambrose Mendy, one of boxing's enduring characters: "Believe me this kid is going to be amazing."

"I've got to a lot to live up to," Eubank said. Dad was ringside and proud of his offspring's performance. Could he be a world champion, the original Eubank was asked. "He's dangerous," he said. He is – and he looks good in a boxing ring.

Eubank is a smooth mover, full of feints and clever little shifts in power, and he throws quite a few more blows per round than did his father, a statuesque boxer in more ways than one.

The lateness of the hour or the excitement of the occasion infected the 10 bells tolled to commemorate the death of Joe Frazier, but the main event restored boxing decorum.